The process of producing radially outwardly pointing teeth or ribs on shafts by using drawing dies is known (DE-AS 2212767).
The problems involved in completely filling the die grooves with material are to be solved in that, in the running-in part of the die, the distance between the groove base and the longitudinal axis of the die is to be increased towards the running-in part, and, if necessary, an increase in the groove width is envisaged as well.
However, experience has shown that the means as proposed do not succeed in completely filling the grooves of the drawing die with material, so that the teeth are slightly inclined inwardly towards the shaft end, i.e. they comprise a reduced tip circle diameter.
At the same time, it is disadvantageous in that distortions may occur even if the axes of the tool and workpiece are aligned.
It is the object of the present invention to design the drawing process and drawing device in such a way that the intended tooth shaped and tooth profile are maintained along the entire length of the tooth to be produced and that any shaft distortions along the axial length are eliminated.
In accordance with the present invention, the objective is achieved in that the shaft is pressed by an actuating force through a drawing die provided with a profile corresponding to the splines to be provided or the shaft, while at the same time subjecting the free end of the shaft to a counter-force which is lower than the actuating force.
By applying the counter-force, it is possible to prevent the free material flow at the shaft end. As a result, the drawing die grooves determining the tooth profile are filled completely, and the drawing operation does not lead to distortion of the shaft to be provided with teeth.
According to an advantageous feature of the present invention, it is proposed that the shaft is pressed through the drawing die by a hydraulically loaded first punch and that a second punch whose diameter is smaller than the envelope circle of the profile of the drawing die passes through the drawing die in the starting position and subjects it to a counter-force.
As the second punch applies the counter-force to the shaft in the starting position, it is ensured that the profile is produced in full along the entire shaft length to be provided with teeth.
According to a second advantageous embodiment of the present invention, the second punch is also loaded hydraulically.
In this way, the counter-force is easily adapted to the actuating force.
According to a process for simultaneously producing splines on both ends of a shaft it is proposed that both ends of the shaft are simultaneously provided with splines, the counter-forge being applied to the two ends of the shaft via second punches arranged on both sides of the shaft and passing through the drawing die associated therewith in each case.
In the case of a device used for carrying out the process, it is proposed that the drawing die is held in a receiving bushing and that the second punch is guided in a guiding bushing held in the receiving means, the second punch, while passing through the drawing die in the starting position, being held by the counter-force.
In the case of a device for carrying out the process of simultaneously producing splines on both ends of a shaft it is proposed that in the horizontal position, the shaft is held by a clamping device and that drawing dies arranged on either side of the shaft may be pressed horizontally against the ends of the shaft by an actuating force adapted to the forming pressure required in each case, with two second punches applying the counter-force being arranged so as to centrally pass through the drawing die.
As a result of the shaft being received centrally in a clamping device, it is also possible to use the process in accordance with the present invention for producing different profiles requiring different actuating forces.